T cell lines and T cell hybridomas for ovalbumin and beef insulin have been produced and tested for specificity by proliferatin, radiobinding and helper/suppressor assays. Characterization of the factor(s) released by these cell lines is currently underway. For the insulin system, B cell hybridoma antibodies are being used to prepared idiotypic reagents which will be tested for T cell reactivity. In other studies, cellular immunity to vaccinia virus in the chimpanzee has been studied using natural killer, MIF, and proliferation assays. HLA and DR typing of the chimpanzee is being carried out in order to determine the genetic basis for viral antigen presentation.